Background: Legacy has been invoked as a means for strengthening human attachments, continuing bonds, and ensuring that individuals will be remembered; however, little is known about the spectrum of approaches to, outcomes associated with, and best practices for legacy interventions. Aim: To systematically review research on legacy perceptions and interventions in pediatric and adult palliative care recipients. Design: A systematic mixed studies review synthesizing quantitative, qualitative, and mixed-methods study findings using PRISMA guidelines. Data sources: PubMed, PsycINFO, and CINAHL databases were searched on October 1, 2020. GRADE criteria were used to assess quality of quantitative reports, and the Johns Hopkins Evidence Level and Quality Guide was used to rate qualitative, mixed methods, and review articles. Data were synthesized using integrative thematic analysis. Results: The 67 studies reviewed describe a variety of legacy perceptions and interventions with adult and pediatric patients receiving palliative care. Statistically significant improvements in various dimensions of wellbeing are documented, with significant reduction in incidence and symptoms of depression in adults. Studies highlight the utility, feasibility, and perceived benefits of legacy interventions according to adult patients and their caregivers, and parents/caregivers of pediatric patients. Conclusions: Though future research with high-quality, experimental designs is needed, the positive outcomes associated with legacy interventions are documented in adult patient populations; additionally, the application of legacy interventions for children with serious illnesses receiving palliative care is reasonable based on the existing body of evidence. A consistent and operational concept of legacy is still needed for future research and practice.